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a(n)=1 for n <= s+k; thereafter a(n) = Sum_{i=0..k-1} a(n-i-s-a(n-i-1)) where s=0, k=6.
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%I #16 Dec 06 2023 11:24:07

%S 1,1,1,1,1,1,6,6,6,6,6,6,11,11,11,11,11,16,11,16,16,16,21,16,21,16,21,

%T 26,21,26,21,26,26,26,31,26,31,31,31,31,31,36,36,36,36,36,36,36,41,41,

%U 41,41,41,46,41,46,46,46,51,46,51,46,51,56,51,56,51,56,56,56,61,56,61,61,61,61,61,66,66,66,66,66

%N a(n)=1 for n <= s+k; thereafter a(n) = Sum_{i=0..k-1} a(n-i-s-a(n-i-1)) where s=0, k=6.

%H N. J. A. Sloane, <a href="/A241155/b241155.txt">Table of n, a(n) for n = 1..20000</a>

%H Joseph Callaghan, John J. Chew III, and Stephen M. Tanny, <a href="https://doi.org/10.1137/S0895480103421397">On the behavior of a family of meta-Fibonacci sequences</a>, SIAM Journal on Discrete Mathematics 18.4 (2005): 794-824. See Eq. (1.7).

%H <a href="/index/Ho#Hofstadter">Index entries for Hofstadter-type sequences</a>

%p #T_s,k(n) from Callaghan et al. Eq. (1.7).

%p s:=0; k:=6;

%p a:=proc(n) option remember; global s,k;

%p if n <= s+k then 1

%p else

%p add(a(n-i-s-a(n-i-1)),i=0..k-1);

%p fi; end;

%p t1:=[seq(a(n),n=1..100)];

%t A241155[n_]:=A241155[n]=If[n<=6,1,Sum[A241155[n-i-A241155[n-i-1]],{i,0,5}]];

%t Array[A241155,100] (* _Paolo Xausa_, Dec 06 2023 *)

%Y Callaghan et al. (2005)'s sequences T_{0,k}(n) for k=1 through 7 are A000012, A046699, A046702, A240835, A241154, A241155, A240830.

%K nonn

%O 1,7

%A _N. J. A. Sloane_, Apr 16 2014